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U.S. Department of Energy June 1999

BASELINE AND TRIAL STANDARD LEVEL RESULTS FOR

THE CONSUMER SUB-GROUP ANALYSIS

FOR RESIDENTIAL WATER HEATER EFFICIENCY STANDARDS

Summary of Results

The consumer sub-group analysis (CSG) examines the economic impacts on different

population groups of consumers from possible revisions to U.S. residential water heater energyefficiency standards. Life-cycle cost represents the consumer's cost of purchasing and installing a

water heater and operating it for its lifetime. The analysis determines whether or not a particular

segment of consumers would be adversely affected from different design option combinations in

terms of reduced or increased life-cycle cost. The mean life-cycle cost change is also estimated.

Negative numbers indicate a life-cycle cost decrease, which is a benefit to consumers. Please refer

to the Life-Cycle Cost Analysis document for details and features of the trial-standard levels.

Summary of Delta LCC Results

Product Class Trial Standard Low-Income Senior-Only

Level Delta LCC Delta LCC

Mean (1998$) % Winners Mean (1998$) % Winners

Electric Trial Standard 1 -55 100 -56 100

Trial Standard 2 -48 98 -51 98

Trial Standard 3 25 22 22 25

Trial Standard 4 25 22 22 25

Gas-Fired Trial Standard 1 -16 100 -17 100

Trial Standard 2 -33 95 -27 90

Trial Standard 3 24 51 29 47

Trial Standard 4 173 7 180 5

Oil-Fired Trial Standard 1 -14 100 -15 100

Trial Standard 2 -14 100 -15 100

Trial Standard 3 -4 73 -8 78

Trial Standard 4 263 0 300 0

The Consumer Sub-Group analysis for water heaters estimates the energy consumption

and life-cycle costs under different trial standard levels for several thousand households. Of

particular interest is the potential effect of standards on households with low-income levels and on

senior-only residents. At the workshop, stakeholders generally agreed that DOE should analyze

the low-income and seniors-only consumer subgroups.

Data Used in the Analysis

Variations in energy use of water heaters between households depends on the following

factors: size and type of water heater, climate, number and age of people in a household, and

presence of hot water-using appliances. Using water heater energy and hot water models, we

estimate annual energy use for several thousand households. The models are derived from test

procedures and field measurements. We used the1993 Residential Energy Consumption Survey

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EE-RM-97-900 COMMENT 77D
(RECS) data for household characteristics in combination with a water use equation and an

energy use equation, (WHAM, see Price-Efficiency Web page) to calculate hot water use, energy

consumption, and fuel price. With data from 5222 of the 7041 RECS households, we account for

the variability of factors between households that affect water heater energy use in the residential

sector.

The 5222 households represent 70,587,617 households in the United States, 73% of the

household population. The households used in the analysis have the following features: (1)

running hot water; (2) the water heater provides hot water to a single-family housing unit; (3) use

one of four fuels (natural gas, LPG, fuel oil, or electricity); (4) billing information that permitted

us to calculate the marginal fuel or electric rate; and (5) information on water heater size. Table 1

shows the composition of the consumer sub-group sample. Tables 2 and 3 show households we

did not use in the analysis. The numbers of housing records in Table 2 do not add up to 1819

because one housing record may fall into more than one category for rejection.

Table 1: Profile of RECS Households Used in Consumer Sub-Group Analysis

Category # of RECS Housing Records % of Household Population (weighted)

Fuel Type Total Low- SeniorIncome Only

Natural Gas 2475 50.9 46.8 50.5

LPG 248 3.6 5.3 4.7

Fuel Oil 176 2.6 1.0 2.6

Electricity 2323 42.9 46.9 42.2

Water Heater Size

Small 1110 21.5 32.8 25.8

Medium 2845 56.0 50.4 51.6

Large 1267 22.5 16.8 22.6

Table 2: Profile of RECS Households Not Used in Consumer Sub-Group Analysis

Category # of RECS Housing Records Household Population (weighted)

Unused Sample Size 1819 25,525,034

# of RECS Housing Records % Household Population (weighted)

Other Fuel Types 54 0.78

Water Heater Size 1151 16.75

Shared WH Unit 742 11.37

Table 3: Number of RECS Households With No Marginal Rate Information

Marginal Rate

Information

No Natural Gas 1104 17.3

No Electric 532 7.3

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EE-RM-97-900 COMMENT 77D
Life-Cycle Cost Determination

DOE uses life-cycle cost (LCC) as the metric to determine consumer impacts. LCC is the

total consumer expense over the life of a water heater, including (1) purchase price, (2)

installation cost, and (3) operating cost. The purchase price and installation costs of baseline

model water heaters came from a database of retail stores and wholesale water heater

distributors.* The operating cost calculation requires knowing three things: (1) the quantity of hot

water used, (2) the amount of energy used, and; (3) the energy price.

The operating cost is largely determined by the amount of hot water used by the

household. The amount of hot water used varies widely between households; it is dependent on:

(1) the number, age, and employment status of the people who live in the home; (2) the climate in

which the home is situated; (3) the presence of hot water-using appliances; (4) the tank size and

thermostat setpoint of the water heater; and (5) whether the household pays for the water heating

fuel. Using these five characteristics, we calculated the average daily hot water use. The average

daily hot water use and the water heater characteristics determine the energy use which, when

combined with the energy cost, results in the operating cost. Figure 1 shows the distribution of

numbers of people in homes across the country. Figure 2 shows the variation in water heater

thermostat setpoint temperature in the United States. Figure 3 shows the average daily hot water

use.

Figure 1: Number of People per Household

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http://www.eren.doe.gov/building/codes_standards/applbrfwaterheater.htm)

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EE-RM-97-900 COMMENT 77D
Figure 2: Water Heater Thermostat Setpoint Temperature

1 dL , _. _~ 

1.-1 12

Figure 3: Daily Hot Water Volume per Person

'.: L-- *-1 ..

By comparing the LCC of all consumers to the LCC of the two consumer sub-groups of

interest, we can determine if the proposed trial standards affect those sub-groups differently. DOE

made these determinations for each trial standard level for low-income and senior-only

households. Figures 4 and 5 show the distribution of low-income and senior-only households

throughout the country. Figures 6 through 8 show the baseline water heater life-cycle cost for

three population groups: the entire sample population, low-income households, and senior-only

households. The baseline level assumes a water-blown baseline water heater for every household.

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EE-RM-97-900 COMMENT 77D
Table 4: Trial Standard Levels for Natural Gas, LPG, Fuel Oil, and Electric Water Heaters

Trial Standard Level Natural Gas and LPG Fuel Oil Electricity

I Heat Traps Heat Traps Heat Traps + Insulated Tank

bottom

2 Heat Traps + 78% RE Flue Heat Traps + 2.5" H20 Heat Traps + 2.5" H20

Baffle + 2" H20 Insulation Insulation Insulation + Insulated Tank

Bottom

3 Heat Traps + 2.5" H20 Heat Traps + 3" H20 Heat Traps + 3" H20

Insulation + 80% RE Flue Insulation + 78% RE + Insulation + Plastic Tank

Baffle Interrupted Ignition

4 Heat Traps, + 3" H20 Heat Traps, + 3" H20 Heat Traps + 3" H20

Insulation + Side Arm Insulation + 82% Heat Insulation + Plastic Tank

Heater + 80% RE Flue Exchanger + Interrupted

Baffle + Plastic Tank Ignition

Figure 4: Low-Income Households, Percentage of Region

'"*.'.

Figure 5: Senior-Only Households, Percentage of Region

_ a N' 'i5

; i~~~~~~

EE-RM-97-900 COMMENT 77D
Figure 6: Life-Cycle Cost for All Households in Sample -- Baseline Level

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Figure 7: Life-Cycle Cost for SeniLow-Income Households - Baseline Level

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3": .1.' .~, .1: ; ' \

Figure 8: Life-Cycle Cost for Senior-Only Households - Baseline Level

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EE-RM-97-900 COMMENT 77D
Figures 9-20 show the changes in life-cycle costs given four standard levels for the entire

sample population, low-income households, and senior-only households. Savings are indicated by

negative numbers. The trial standard levels are shown in Table 4.

Figure 9: Delta Life-Cycle Cost for All Households in Sample - Trial Standard Level One

*^-. .*. -n

Figure 10: Delta Life-Cycle Cost for Low-Income Households - Trial Standard Level One

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Figure 11: Delta Life-Cycle Cost for Senior-Only Households - Trial Standard Level One

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7

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Fiue 1Det Lf-Cce ot o SmrOnyHoshod -Tia tadrdLven

EE-RM-97-900 COMMENT 77D
Overall, referring to Figure 13, Delta LCC for low income households, for trial standard

level two, one can see that most of the US regions benefit by $50 while some may have up to

$150 benefit. These benefits outweigh the region of Montana and eastern Washington that has an

adverse impact up to $50. Similarly, in figure 14, benefits outweigh the adverse impacts but to a

slightly lesser extent.

Figure 12: Delta Life-Cycle Cost for All Households in Sample - Trial Standard Level Two

~ :: ' -.-. is.-, XI

II. 2

Figure 13: Delta Life-Cycle Cost for Low-Income Households - Trial Standard Level Two

(.*- .

Figure 14: Delta Life-Cycle Cost for Senior-Only Households - Trial Standard Level Two

m ' '2:i

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EE-RM-97-900 COMMENT 77D
Figure 15: Delta Life-Cycle Cost for All Households in Sample - Trial Standard Level Three

'*.d'..'1 .'1 I

Figure 16: Delta Life-Cycle Cost for Low-Income Households - Trial Standard Level Three

I- . I: 

Figure 17: Delta Life-Cycle Cost for Senior-Only Households - Trial Standard Level Three

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EE-RM-97-900 COMMENT 77D
Figure 18: Delta Life-Cycle Cost for All Households in Sample - Trial Standard Level Four

Figure 19: Delta Life-Cycle Cost for Low-Income Households - Trial Standard Level Four

f :--+ ·

Figure 20: Delta Life-Cycle Cost for Senior-Only Households - Trial Standard Level Four

" $»1: _ . r

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EE-RM-97-900 COMMENT 77D